regulator: axp20x: Mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Notice that in this particular case, I moved the whole comment
"Fall through to the check below.", which contains the "Fall through"
comment, at the bottom of the case, which is what GCC is expecting
to find.

Addresses-Coverity-ID: 1436594 ("Missing break in switch")
Addresses-Coverity-ID: 1364475 ("Missing break in switch")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/regulator/axp20x-regulator.c

@@ -509,10 +509,10 @@ static int axp20x_set_dcdc_freq(struct platform_device *pdev, u32 dcdcfreq)
 		/*
 		 * AXP803/AXP813 DCDC work frequency setting has the same
 		 * range and step as AXP22X, but at a different register.
-		 * Fall through to the check below.
 		 * (See include/linux/mfd/axp20x.h)
 		 */
 		reg = AXP803_DCDC_FREQ_CTRL;
+		/* Fall through to the check below.*/
 	case AXP806_ID:
 		/*
 		 * AXP806 also have DCDC work frequency setting register at a
@@ -520,6 +520,7 @@ static int axp20x_set_dcdc_freq(struct platform_device *pdev, u32 dcdcfreq)
 		 */
 		if (axp20x->variant == AXP806_ID)
 			reg = AXP806_DCDC_FREQ_CTRL;
+		/* Fall through */
 	case AXP221_ID:
 	case AXP223_ID:
 	case AXP809_ID: